Description of problem:
It's possible for retrace-server to retrace successfully a vmcore in a tarball and end up with a 'crash' directory underneath the task that is unreadable by anything other than the user (retrace).  This means anyone trying to run 'retrace-server-interact' will get a "No such file or directory" error, and the vmcore is unusable from the perspective of interact mode.

Any tarball that contains a 'cwd' which is unreadable this happens.  For example:
tar -cvf /tmp/rhel7u2-node1-vmcore.tgz ./
./
./vmcore-dmesg.txt
./vmcore
$ tar -tvf /tmp/rhel7u2-node1-vmcore.tgz 
drwx------ user/user 0 2017-08-14 16:57 ./
-rw-r--r-- user/user 42425 2015-11-24 10:14 ./vmcore-dmesg.txt
-rw------- user/user 44915206 2015-11-24 10:14 ./vmcore

$ retrace-server-interact 332586857 crash
If you want to execute the command manually, you can run
$ crash -i /cores/retrace/tasks/332586857/crashrc /cores/retrace/tasks/332586857/crash/vmcore /cores/retrace/repos/kernel/x86_64/usr/lib/debug/lib/modules/3.10.0-327.el7.x86_64/vmlinux


crash 7.1.9
Copyright (C) 2002-2016  Red Hat, Inc.
Copyright (C) 2004, 2005, 2006, 2010  IBM Corporation
Copyright (C) 1999-2006  Hewlett-Packard Co
Copyright (C) 2005, 2006, 2011, 2012  Fujitsu Limited
Copyright (C) 2006, 2007  VA Linux Systems Japan K.K.
Copyright (C) 2005, 2011  NEC Corporation
Copyright (C) 1999, 2002, 2007  Silicon Graphics, Inc.
Copyright (C) 1999, 2000, 2001, 2002  Mission Critical Linux, Inc.
This program is free software, covered by the GNU General Public License,
and you are welcome to change it and/or distribute copies of it under
certain conditions.  Enter "help copying" to see the conditions.
This program has absolutely no warranty.  Enter "help warranty" for details.
 
crash: /cores/retrace/tasks/332586857/crash/vmcore: No such file or directory

Usage:

  crash [OPTION]... NAMELIST MEMORY-IMAGE[@ADDRESS]     (dumpfile form)
  crash [OPTION]... [NAMELIST]                          (live system form)

Enter "crash -h" for details.
$ ls -ld /cores/retrace/tasks/332586857/crash
drwx-w----. 2 retrace retrace-group 27 Aug 14 17:10 /cores/retrace/tasks/332586857/crash
$ ls -l /cores/retrace/tasks/332586857/crash/vmcore
ls: cannot access /cores/retrace/tasks/332586857/crash/vmcore: Permission denied



Version-Release number of selected component (if applicable):
retrace-server-1.17.0-3.el6.noarch

$ rpm -q retrace-server --changelog | head
* Thu Apr 06 2017 Dave Wysochanski <dwysocha> 1.17.0-3
- Fix problem with missing modules on kernel versions with cached vmlinux files.
- Fix typeo in manager.wsgi which creates a backtrace on non-ftp tasks.

* Thu Mar 30 2017 Matej Marusak <mmarusak> 1.17.0-1
- Enable creating releases with makefile
- Introduce gen-version
- Do not use fedorahosted.org as source
- Include md5sum of original archive in summary page
- Do not try to get default time when ftptask


How reproducible:
Trivial


Steps to Reproduce:
1. Submit a vmcore to retrace-server inside a tarball with the 'cwd' containing only user readable permissions

Actual results:
the vmcore is extracted and setup ok with a task directory, but the 'crash' subdirectory containing the vmcore is not readable by anything other than user (retrace)

Expected results:
the 'crash' subdirectory is group readable so users can use interactive mode on the vmcore

Additional info:
Note that this first came in via an 'abrt' tarball.  Can't say yet but this may have been there for a long time.  It is similar to an earlier fixed bug, https://bugzilla.redhat.com/show_bug.cgi?id=1076833, but this one deals with the crash subdirectory specifically, not the vmcore file.  My guess is abrt team did not see this yet due to the fact that they do not use interactive mode, and it is a corner case that may not happen too often.

I will attach a tarball containing a vmcore to reproduce this issue.